1. Field of the Invention
This invention relates to lens cleaning devices, particularly those having concave pads thereon, lens cleaning compositions, in particular compositions including carbon black, and methods for cleaning lenses using such devices and compositions.
2. Description of Related Art
Articles and instruments such as cameras, lens, binoculars, telescopes, view finders, magnifiers, theodolites and other devices having optical surfaces performed best when the optical surfaces are kept clean. On the one hand, the cleaning must be sufficient to remove fingerprints, dust, oily deposits and greasy or rain water residues. On the other hand, the cleaning must not damage relatively delicate plastic or optically coated surfaces.
Commonly a brush or blower, or a combination of both, is used to clean camera lenses and the like. However, these devices are really only effective in removing dust, sand and other loose particles. Fingerprints and other more permanent residues are usually removed using a soft cloth, chamois or tissue paper with or without a cleaning fluid.
Various articles have been developed to hold and support such means for wiping lenses. Examples are found in U.S. Pat. No. 2,055,314 to Seburger, 2,458,015 to McDonald, 2,880,441 to Rushing Jr., 4,480,252 to Eggett and 4,546,517 to Caniglia.
Such prior art devices and methods have certain limitations and disadvantages. For example, blowers or brushes merely remove dust or loose particles. Wiping devices and materials do not quickly or effectively remove greasy residues when used dry and may spread oily spots over the cleaned surfaces, causing flare and diffusion of the image. The use of a solvent is helpful, but this means that the user must carry around a bottle of solvent which has to be opened, applied, and wiped dry with a tissue or other wiper which is relatively inconvenient. In addition, disposable tissues contribute to litter when they are tossed away by careless users. Thus the prior art creates the need for a more effective and convenient lens cleaner and lens cleaning method.